<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="">
性别:
<input type="radio" name="sex"/>男
<!-- checked属性是默认选中 -->
<input type="radio" name="sex" checked="checked">女<br/>
兴趣:
<input type="checkbox" name="hobby"/>唱歌
<input type="checkbox" name="hobby"/>跳舞
<input type="checkbox" name="hobby" checked="checked"/>下棋<br/>
年级:
<select id="grade" name="grade">
	<option value="1">大一</option>
	<option value="2">大二</option>
	<option value="3">大三</option>
</select>
</form>
</body>
</html>